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caif-hsi: Fix merge issues.
[linux-2.6-block.git] / drivers / net / xen-netback / netback.c
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f942dc25
IC		 1/*
2 * Back-end of the driver for virtual network devices. This portion of the
3 * driver exports a 'unified' network-device interface that can be accessed
4 * by any operating system that implements a compatible front end. A
5 * reference front-end implementation can be found in:
6 * drivers/net/xen-netfront.c
7 *
8 * Copyright (c) 2002-2005, K A Fraser
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License version 2
12 * as published by the Free Software Foundation; or, when distributed
13 * separately from the Linux kernel or incorporated into other
14 * software packages, subject to the following license:
15 *
16 * Permission is hereby granted, free of charge, to any person obtaining a copy
17 * of this source file (the "Software"), to deal in the Software without
18 * restriction, including without limitation the rights to use, copy, modify,
19 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
20 * and to permit persons to whom the Software is furnished to do so, subject to
21 * the following conditions:
22 *
23 * The above copyright notice and this permission notice shall be included in
24 * all copies or substantial portions of the Software.
25 *
26 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
27 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
28 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
29 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
30 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
31 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
32 * IN THE SOFTWARE.
33 */
34
35#include "common.h"
36
37#include <linux/kthread.h>
38#include <linux/if_vlan.h>
39#include <linux/udp.h>
40
41#include <net/tcp.h>
42
43#include <xen/events.h>
44#include <xen/interface/memory.h>
45
46#include <asm/xen/hypercall.h>
47#include <asm/xen/page.h>
48
49struct pending_tx_info {
50 struct xen_netif_tx_request req;
51 struct xenvif *vif;
52};
53typedef unsigned int pending_ring_idx_t;
54
55struct netbk_rx_meta {
56 int id;
57 int size;
58 int gso_size;
59};
60
61#define MAX_PENDING_REQS 256
62
ea066ad1
IC		 63/* Discriminate from any valid pending_idx value. */
64#define INVALID_PENDING_IDX 0xFFFF
65
f942dc25
IC		 66#define MAX_BUFFER_OFFSET PAGE_SIZE
67
68/* extra field used in struct page */
69union page_ext {
70 struct {
71#if BITS_PER_LONG < 64
72#define IDX_WIDTH 8
73#define GROUP_WIDTH (BITS_PER_LONG - IDX_WIDTH)
74 unsigned int group:GROUP_WIDTH;
75 unsigned int idx:IDX_WIDTH;
76#else
77 unsigned int group, idx;
78#endif
79 } e;
80 void *mapping;
81};
82
83struct xen_netbk {
84 wait_queue_head_t wq;
85 struct task_struct *task;
86
87 struct sk_buff_head rx_queue;
88 struct sk_buff_head tx_queue;
89
90 struct timer_list net_timer;
91
92 struct page *mmap_pages[MAX_PENDING_REQS];
93
94 pending_ring_idx_t pending_prod;
95 pending_ring_idx_t pending_cons;
96 struct list_head net_schedule_list;
97
98 /* Protect the net_schedule_list in netif. */
99 spinlock_t net_schedule_list_lock;
100
101 atomic_t netfront_count;
102
103 struct pending_tx_info pending_tx_info[MAX_PENDING_REQS];
104 struct gnttab_copy tx_copy_ops[MAX_PENDING_REQS];
105
106 u16 pending_ring[MAX_PENDING_REQS];
107
108 /*
109 * Given MAX_BUFFER_OFFSET of 4096 the worst case is that each
110 * head/fragment page uses 2 copy operations because it
111 * straddles two buffers in the frontend.
112 */
113 struct gnttab_copy grant_copy_op[2*XEN_NETIF_RX_RING_SIZE];
114 struct netbk_rx_meta meta[2*XEN_NETIF_RX_RING_SIZE];
115};
116
117static struct xen_netbk *xen_netbk;
118static int xen_netbk_group_nr;
119
120void xen_netbk_add_xenvif(struct xenvif *vif)
121{
122 int i;
123 int min_netfront_count;
124 int min_group = 0;
125 struct xen_netbk *netbk;
126
127 min_netfront_count = atomic_read(&xen_netbk[0].netfront_count);
128 for (i = 0; i < xen_netbk_group_nr; i++) {
129 int netfront_count = atomic_read(&xen_netbk[i].netfront_count);
130 if (netfront_count < min_netfront_count) {
131 min_group = i;
132 min_netfront_count = netfront_count;
133 }
134 }
135
136 netbk = &xen_netbk[min_group];
137
138 vif->netbk = netbk;
139 atomic_inc(&netbk->netfront_count);
140}
141
142void xen_netbk_remove_xenvif(struct xenvif *vif)
143{
144 struct xen_netbk *netbk = vif->netbk;
145 vif->netbk = NULL;
146 atomic_dec(&netbk->netfront_count);
147}
148
149static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx);
150static void make_tx_response(struct xenvif *vif,
151 struct xen_netif_tx_request *txp,
152 s8 st);
153static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
154 u16 id,
155 s8 st,
156 u16 offset,
157 u16 size,
158 u16 flags);
159
160static inline unsigned long idx_to_pfn(struct xen_netbk *netbk,
ea066ad1 161 u16 idx)
f942dc25
IC		 162{
163 return page_to_pfn(netbk->mmap_pages[idx]);
164}
165
166static inline unsigned long idx_to_kaddr(struct xen_netbk *netbk,
ea066ad1 167 u16 idx)
f942dc25
IC		 168{
169 return (unsigned long)pfn_to_kaddr(idx_to_pfn(netbk, idx));
170}
171
172/* extra field used in struct page */
173static inline void set_page_ext(struct page *pg, struct xen_netbk *netbk,
174 unsigned int idx)
175{
176 unsigned int group = netbk - xen_netbk;
177 union page_ext ext = { .e = { .group = group + 1, .idx = idx } };
178
179 BUILD_BUG_ON(sizeof(ext) > sizeof(ext.mapping));
180 pg->mapping = ext.mapping;
181}
182
183static int get_page_ext(struct page *pg,
184 unsigned int *pgroup, unsigned int *pidx)
185{
186 union page_ext ext = { .mapping = pg->mapping };
187 struct xen_netbk *netbk;
188 unsigned int group, idx;
189
190 group = ext.e.group - 1;
191
192 if (group < 0 || group >= xen_netbk_group_nr)
193 return 0;
194
195 netbk = &xen_netbk[group];
196
197 idx = ext.e.idx;
198
199 if ((idx < 0) || (idx >= MAX_PENDING_REQS))
200 return 0;
201
202 if (netbk->mmap_pages[idx] != pg)
203 return 0;
204
205 *pgroup = group;
206 *pidx = idx;
207
208 return 1;
209}
210
211/*
212 * This is the amount of packet we copy rather than map, so that the
213 * guest can't fiddle with the contents of the headers while we do
214 * packet processing on them (netfilter, routing, etc).
215 */
216#define PKT_PROT_LEN (ETH_HLEN + \
217 VLAN_HLEN + \
218 sizeof(struct iphdr) + MAX_IPOPTLEN + \
219 sizeof(struct tcphdr) + MAX_TCP_OPTION_SPACE)
220
ea066ad1
IC		 221static u16 frag_get_pending_idx(skb_frag_t *frag)
222{
223 return (u16)frag->page_offset;
224}
225
226static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
227{
228 frag->page_offset = pending_idx;
229}
230
f942dc25
IC		 231static inline pending_ring_idx_t pending_index(unsigned i)
232{
233 return i & (MAX_PENDING_REQS-1);
234}
235
236static inline pending_ring_idx_t nr_pending_reqs(struct xen_netbk *netbk)
237{
238 return MAX_PENDING_REQS -
239 netbk->pending_prod + netbk->pending_cons;
240}
241
242static void xen_netbk_kick_thread(struct xen_netbk *netbk)
243{
244 wake_up(&netbk->wq);
245}
246
247static int max_required_rx_slots(struct xenvif *vif)
248{
249 int max = DIV_ROUND_UP(vif->dev->mtu, PAGE_SIZE);
250
251 if (vif->can_sg || vif->gso || vif->gso_prefix)
252 max += MAX_SKB_FRAGS + 1; /* extra_info + frags */
253
254 return max;
255}
256
257int xen_netbk_rx_ring_full(struct xenvif *vif)
258{
259 RING_IDX peek = vif->rx_req_cons_peek;
260 RING_IDX needed = max_required_rx_slots(vif);
261
262 return ((vif->rx.sring->req_prod - peek) < needed) ||
263 ((vif->rx.rsp_prod_pvt + XEN_NETIF_RX_RING_SIZE - peek) < needed);
264}
265
266int xen_netbk_must_stop_queue(struct xenvif *vif)
267{
268 if (!xen_netbk_rx_ring_full(vif))
269 return 0;
270
271 vif->rx.sring->req_event = vif->rx_req_cons_peek +
272 max_required_rx_slots(vif);
273 mb(); /* request notification /then/ check the queue */
274
275 return xen_netbk_rx_ring_full(vif);
276}
277
278/*
279 * Returns true if we should start a new receive buffer instead of
280 * adding 'size' bytes to a buffer which currently contains 'offset'
281 * bytes.
282 */
283static bool start_new_rx_buffer(int offset, unsigned long size, int head)
284{
285 /* simple case: we have completely filled the current buffer. */
286 if (offset == MAX_BUFFER_OFFSET)
287 return true;
288
289 /*
290 * complex case: start a fresh buffer if the current frag
291 * would overflow the current buffer but only if:
292 * (i) this frag would fit completely in the next buffer
293 * and (ii) there is already some data in the current buffer
294 * and (iii) this is not the head buffer.
295 *
296 * Where:
297 * - (i) stops us splitting a frag into two copies
298 * unless the frag is too large for a single buffer.
299 * - (ii) stops us from leaving a buffer pointlessly empty.
300 * - (iii) stops us leaving the first buffer
301 * empty. Strictly speaking this is already covered
302 * by (ii) but is explicitly checked because
303 * netfront relies on the first buffer being
304 * non-empty and can crash otherwise.
305 *
306 * This means we will effectively linearise small
307 * frags but do not needlessly split large buffers
308 * into multiple copies tend to give large frags their
309 * own buffers as before.
310 */
311 if ((offset + size > MAX_BUFFER_OFFSET) &&
312 (size <= MAX_BUFFER_OFFSET) && offset && !head)
313 return true;
314
315 return false;
316}
317
318/*
319 * Figure out how many ring slots we're going to need to send @skb to
320 * the guest. This function is essentially a dry run of
321 * netbk_gop_frag_copy.
322 */
323unsigned int xen_netbk_count_skb_slots(struct xenvif *vif, struct sk_buff *skb)
324{
325 unsigned int count;
326 int i, copy_off;
327
e26b203e 328 count = DIV_ROUND_UP(skb_headlen(skb), PAGE_SIZE);
f942dc25
IC		 329
330 copy_off = skb_headlen(skb) % PAGE_SIZE;
331
332 if (skb_shinfo(skb)->gso_size)
333 count++;
334
335 for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
9e903e08 336 unsigned long size = skb_frag_size(&skb_shinfo(skb)->frags[i]);
f942dc25
IC		 337 unsigned long bytes;
338 while (size > 0) {
339 BUG_ON(copy_off > MAX_BUFFER_OFFSET);
340
341 if (start_new_rx_buffer(copy_off, size, 0)) {
342 count++;
343 copy_off = 0;
344 }
345
346 bytes = size;
347 if (copy_off + bytes > MAX_BUFFER_OFFSET)
348 bytes = MAX_BUFFER_OFFSET - copy_off;
349
350 copy_off += bytes;
351 size -= bytes;
352 }
353 }
354 return count;
355}
356
357struct netrx_pending_operations {
358 unsigned copy_prod, copy_cons;
359 unsigned meta_prod, meta_cons;
360 struct gnttab_copy *copy;
361 struct netbk_rx_meta *meta;
362 int copy_off;
363 grant_ref_t copy_gref;
364};
365
366static struct netbk_rx_meta *get_next_rx_buffer(struct xenvif *vif,
367 struct netrx_pending_operations *npo)
368{
369 struct netbk_rx_meta *meta;
370 struct xen_netif_rx_request *req;
371
372 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
373
374 meta = npo->meta + npo->meta_prod++;
375 meta->gso_size = 0;
376 meta->size = 0;
377 meta->id = req->id;
378
379 npo->copy_off = 0;
380 npo->copy_gref = req->gref;
381
382 return meta;
383}
384
385/*
386 * Set up the grant operations for this fragment. If it's a flipping
387 * interface, we also set up the unmap request from here.
388 */
389static void netbk_gop_frag_copy(struct xenvif *vif, struct sk_buff *skb,
390 struct netrx_pending_operations *npo,
391 struct page *page, unsigned long size,
392 unsigned long offset, int *head)
393{
394 struct gnttab_copy *copy_gop;
395 struct netbk_rx_meta *meta;
396 /*
e34c0246 397 * These variables are used iff get_page_ext returns true,
f942dc25
IC		 398 * in which case they are guaranteed to be initialized.
399 */
400 unsigned int uninitialized_var(group), uninitialized_var(idx);
401 int foreign = get_page_ext(page, &group, &idx);
402 unsigned long bytes;
403
404 /* Data must not cross a page boundary. */
405 BUG_ON(size + offset > PAGE_SIZE);
406
407 meta = npo->meta + npo->meta_prod - 1;
408
409 while (size > 0) {
410 BUG_ON(npo->copy_off > MAX_BUFFER_OFFSET);
411
412 if (start_new_rx_buffer(npo->copy_off, size, *head)) {
413 /*
414 * Netfront requires there to be some data in the head
415 * buffer.
416 */
417 BUG_ON(*head);
418
419 meta = get_next_rx_buffer(vif, npo);
420 }
421
422 bytes = size;
423 if (npo->copy_off + bytes > MAX_BUFFER_OFFSET)
424 bytes = MAX_BUFFER_OFFSET - npo->copy_off;
425
426 copy_gop = npo->copy + npo->copy_prod++;
427 copy_gop->flags = GNTCOPY_dest_gref;
428 if (foreign) {
429 struct xen_netbk *netbk = &xen_netbk[group];
430 struct pending_tx_info *src_pend;
431
432 src_pend = &netbk->pending_tx_info[idx];
433
434 copy_gop->source.domid = src_pend->vif->domid;
435 copy_gop->source.u.ref = src_pend->req.gref;
436 copy_gop->flags |= GNTCOPY_source_gref;
437 } else {
438 void *vaddr = page_address(page);
439 copy_gop->source.domid = DOMID_SELF;
440 copy_gop->source.u.gmfn = virt_to_mfn(vaddr);
441 }
442 copy_gop->source.offset = offset;
443 copy_gop->dest.domid = vif->domid;
444
445 copy_gop->dest.offset = npo->copy_off;
446 copy_gop->dest.u.ref = npo->copy_gref;
447 copy_gop->len = bytes;
448
449 npo->copy_off += bytes;
450 meta->size += bytes;
451
452 offset += bytes;
453 size -= bytes;
454
455 /* Leave a gap for the GSO descriptor. */
456 if (*head && skb_shinfo(skb)->gso_size && !vif->gso_prefix)
457 vif->rx.req_cons++;
458
459 *head = 0; /* There must be something in this buffer now. */
460
461 }
462}
463
464/*
465 * Prepare an SKB to be transmitted to the frontend.
466 *
467 * This function is responsible for allocating grant operations, meta
468 * structures, etc.
469 *
470 * It returns the number of meta structures consumed. The number of
471 * ring slots used is always equal to the number of meta slots used
472 * plus the number of GSO descriptors used. Currently, we use either
473 * zero GSO descriptors (for non-GSO packets) or one descriptor (for
474 * frontend-side LRO).
475 */
476static int netbk_gop_skb(struct sk_buff *skb,
477 struct netrx_pending_operations *npo)
478{
479 struct xenvif *vif = netdev_priv(skb->dev);
480 int nr_frags = skb_shinfo(skb)->nr_frags;
481 int i;
482 struct xen_netif_rx_request *req;
483 struct netbk_rx_meta *meta;
484 unsigned char *data;
485 int head = 1;
486 int old_meta_prod;
487
488 old_meta_prod = npo->meta_prod;
489
490 /* Set up a GSO prefix descriptor, if necessary */
491 if (skb_shinfo(skb)->gso_size && vif->gso_prefix) {
492 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
493 meta = npo->meta + npo->meta_prod++;
494 meta->gso_size = skb_shinfo(skb)->gso_size;
495 meta->size = 0;
496 meta->id = req->id;
497 }
498
499 req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
500 meta = npo->meta + npo->meta_prod++;
501
502 if (!vif->gso_prefix)
503 meta->gso_size = skb_shinfo(skb)->gso_size;
504 else
505 meta->gso_size = 0;
506
507 meta->size = 0;
508 meta->id = req->id;
509 npo->copy_off = 0;
510 npo->copy_gref = req->gref;
511
512 data = skb->data;
513 while (data < skb_tail_pointer(skb)) {
514 unsigned int offset = offset_in_page(data);
515 unsigned int len = PAGE_SIZE - offset;
516
517 if (data + len > skb_tail_pointer(skb))
518 len = skb_tail_pointer(skb) - data;
519
520 netbk_gop_frag_copy(vif, skb, npo,
521 virt_to_page(data), len, offset, &head);
522 data += len;
523 }
524
525 for (i = 0; i < nr_frags; i++) {
526 netbk_gop_frag_copy(vif, skb, npo,
ea066ad1 527 skb_frag_page(&skb_shinfo(skb)->frags[i]),
9e903e08 528 skb_frag_size(&skb_shinfo(skb)->frags[i]),
f942dc25
IC		 529 skb_shinfo(skb)->frags[i].page_offset,
530 &head);
531 }
532
533 return npo->meta_prod - old_meta_prod;
534}
535
536/*
537 * This is a twin to netbk_gop_skb. Assume that netbk_gop_skb was
538 * used to set up the operations on the top of
539 * netrx_pending_operations, which have since been done. Check that
540 * they didn't give any errors and advance over them.
541 */
542static int netbk_check_gop(struct xenvif *vif, int nr_meta_slots,
543 struct netrx_pending_operations *npo)
544{
545 struct gnttab_copy *copy_op;
546 int status = XEN_NETIF_RSP_OKAY;
547 int i;
548
549 for (i = 0; i < nr_meta_slots; i++) {
550 copy_op = npo->copy + npo->copy_cons++;
551 if (copy_op->status != GNTST_okay) {
552 netdev_dbg(vif->dev,
553 "Bad status %d from copy to DOM%d.\n",
554 copy_op->status, vif->domid);
555 status = XEN_NETIF_RSP_ERROR;
556 }
557 }
558
559 return status;
560}
561
562static void netbk_add_frag_responses(struct xenvif *vif, int status,
563 struct netbk_rx_meta *meta,
564 int nr_meta_slots)
565{
566 int i;
567 unsigned long offset;
568
569 /* No fragments used */
570 if (nr_meta_slots <= 1)
571 return;
572
573 nr_meta_slots--;
574
575 for (i = 0; i < nr_meta_slots; i++) {
576 int flags;
577 if (i == nr_meta_slots - 1)
578 flags = 0;
579 else
580 flags = XEN_NETRXF_more_data;
581
582 offset = 0;
583 make_rx_response(vif, meta[i].id, status, offset,
584 meta[i].size, flags);
585 }
586}
587
588struct skb_cb_overlay {
589 int meta_slots_used;
590};
591
592static void xen_netbk_rx_action(struct xen_netbk *netbk)
593{
594 struct xenvif *vif = NULL, *tmp;
595 s8 status;
596 u16 irq, flags;
597 struct xen_netif_rx_response *resp;
598 struct sk_buff_head rxq;
599 struct sk_buff *skb;
600 LIST_HEAD(notify);
601 int ret;
602 int nr_frags;
603 int count;
604 unsigned long offset;
605 struct skb_cb_overlay *sco;
606
607 struct netrx_pending_operations npo = {
608 .copy = netbk->grant_copy_op,
609 .meta = netbk->meta,
610 };
611
612 skb_queue_head_init(&rxq);
613
614 count = 0;
615
616 while ((skb = skb_dequeue(&netbk->rx_queue)) != NULL) {
617 vif = netdev_priv(skb->dev);
618 nr_frags = skb_shinfo(skb)->nr_frags;
619
620 sco = (struct skb_cb_overlay *)skb->cb;
621 sco->meta_slots_used = netbk_gop_skb(skb, &npo);
622
623 count += nr_frags + 1;
624
625 __skb_queue_tail(&rxq, skb);
626
627 /* Filled the batch queue? */
628 if (count + MAX_SKB_FRAGS >= XEN_NETIF_RX_RING_SIZE)
629 break;
630 }
631
632 BUG_ON(npo.meta_prod > ARRAY_SIZE(netbk->meta));
633
634 if (!npo.copy_prod)
635 return;
636
637 BUG_ON(npo.copy_prod > ARRAY_SIZE(netbk->grant_copy_op));
638 ret = HYPERVISOR_grant_table_op(GNTTABOP_copy, &netbk->grant_copy_op,
639 npo.copy_prod);
640 BUG_ON(ret != 0);
641
642 while ((skb = __skb_dequeue(&rxq)) != NULL) {
643 sco = (struct skb_cb_overlay *)skb->cb;
644
645 vif = netdev_priv(skb->dev);
646
647 if (netbk->meta[npo.meta_cons].gso_size && vif->gso_prefix) {
648 resp = RING_GET_RESPONSE(&vif->rx,
649 vif->rx.rsp_prod_pvt++);
650
651 resp->flags = XEN_NETRXF_gso_prefix | XEN_NETRXF_more_data;
652
653 resp->offset = netbk->meta[npo.meta_cons].gso_size;
654 resp->id = netbk->meta[npo.meta_cons].id;
655 resp->status = sco->meta_slots_used;
656
657 npo.meta_cons++;
658 sco->meta_slots_used--;
659 }
660
661
662 vif->dev->stats.tx_bytes += skb->len;
663 vif->dev->stats.tx_packets++;
664
665 status = netbk_check_gop(vif, sco->meta_slots_used, &npo);
666
667 if (sco->meta_slots_used == 1)
668 flags = 0;
669 else
670 flags = XEN_NETRXF_more_data;
671
672 if (skb->ip_summed == CHECKSUM_PARTIAL) /* local packet? */
673 flags |= XEN_NETRXF_csum_blank | XEN_NETRXF_data_validated;
674 else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
675 /* remote but checksummed. */
676 flags |= XEN_NETRXF_data_validated;
677
678 offset = 0;
679 resp = make_rx_response(vif, netbk->meta[npo.meta_cons].id,
680 status, offset,
681 netbk->meta[npo.meta_cons].size,
682 flags);
683
684 if (netbk->meta[npo.meta_cons].gso_size && !vif->gso_prefix) {
685 struct xen_netif_extra_info *gso =
686 (struct xen_netif_extra_info *)
687 RING_GET_RESPONSE(&vif->rx,
688 vif->rx.rsp_prod_pvt++);
689
690 resp->flags |= XEN_NETRXF_extra_info;
691
692 gso->u.gso.size = netbk->meta[npo.meta_cons].gso_size;
693 gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
694 gso->u.gso.pad = 0;
695 gso->u.gso.features = 0;
696
697 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
698 gso->flags = 0;
699 }
700
701 netbk_add_frag_responses(vif, status,
702 netbk->meta + npo.meta_cons + 1,
703 sco->meta_slots_used);
704
705 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->rx, ret);
706 irq = vif->irq;
707 if (ret && list_empty(&vif->notify_list))
708 list_add_tail(&vif->notify_list, &notify);
709
710 xenvif_notify_tx_completion(vif);
711
712 xenvif_put(vif);
713 npo.meta_cons += sco->meta_slots_used;
714 dev_kfree_skb(skb);
715 }
716
717 list_for_each_entry_safe(vif, tmp, &notify, notify_list) {
718 notify_remote_via_irq(vif->irq);
719 list_del_init(&vif->notify_list);
720 }
721
722 /* More work to do? */
723 if (!skb_queue_empty(&netbk->rx_queue) &&
724 !timer_pending(&netbk->net_timer))
725 xen_netbk_kick_thread(netbk);
726}
727
728void xen_netbk_queue_tx_skb(struct xenvif *vif, struct sk_buff *skb)
729{
730 struct xen_netbk *netbk = vif->netbk;
731
732 skb_queue_tail(&netbk->rx_queue, skb);
733
734 xen_netbk_kick_thread(netbk);
735}
736
737static void xen_netbk_alarm(unsigned long data)
738{
739 struct xen_netbk *netbk = (struct xen_netbk *)data;
740 xen_netbk_kick_thread(netbk);
741}
742
743static int __on_net_schedule_list(struct xenvif *vif)
744{
745 return !list_empty(&vif->schedule_list);
746}
747
748/* Must be called with net_schedule_list_lock held */
749static void remove_from_net_schedule_list(struct xenvif *vif)
750{
751 if (likely(__on_net_schedule_list(vif))) {
752 list_del_init(&vif->schedule_list);
753 xenvif_put(vif);
754 }
755}
756
757static struct xenvif *poll_net_schedule_list(struct xen_netbk *netbk)
758{
759 struct xenvif *vif = NULL;
760
761 spin_lock_irq(&netbk->net_schedule_list_lock);
762 if (list_empty(&netbk->net_schedule_list))
763 goto out;
764
765 vif = list_first_entry(&netbk->net_schedule_list,
766 struct xenvif, schedule_list);
767 if (!vif)
768 goto out;
769
770 xenvif_get(vif);
771
772 remove_from_net_schedule_list(vif);
773out:
774 spin_unlock_irq(&netbk->net_schedule_list_lock);
775 return vif;
776}
777
778void xen_netbk_schedule_xenvif(struct xenvif *vif)
779{
780 unsigned long flags;
781 struct xen_netbk *netbk = vif->netbk;
782
783 if (__on_net_schedule_list(vif))
784 goto kick;
785
786 spin_lock_irqsave(&netbk->net_schedule_list_lock, flags);
787 if (!__on_net_schedule_list(vif) &&
788 likely(xenvif_schedulable(vif))) {
789 list_add_tail(&vif->schedule_list, &netbk->net_schedule_list);
790 xenvif_get(vif);
791 }
792 spin_unlock_irqrestore(&netbk->net_schedule_list_lock, flags);
793
794kick:
795 smp_mb();
796 if ((nr_pending_reqs(netbk) < (MAX_PENDING_REQS/2)) &&
797 !list_empty(&netbk->net_schedule_list))
798 xen_netbk_kick_thread(netbk);
799}
800
801void xen_netbk_deschedule_xenvif(struct xenvif *vif)
802{
803 struct xen_netbk *netbk = vif->netbk;
804 spin_lock_irq(&netbk->net_schedule_list_lock);
805 remove_from_net_schedule_list(vif);
806 spin_unlock_irq(&netbk->net_schedule_list_lock);
807}
808
809void xen_netbk_check_rx_xenvif(struct xenvif *vif)
810{
811 int more_to_do;
812
813 RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, more_to_do);
814
815 if (more_to_do)
816 xen_netbk_schedule_xenvif(vif);
817}
818
819static void tx_add_credit(struct xenvif *vif)
820{
821 unsigned long max_burst, max_credit;
822
823 /*
824 * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
825 * Otherwise the interface can seize up due to insufficient credit.
826 */
827 max_burst = RING_GET_REQUEST(&vif->tx, vif->tx.req_cons)->size;
828 max_burst = min(max_burst, 131072UL);
829 max_burst = max(max_burst, vif->credit_bytes);
830
831 /* Take care that adding a new chunk of credit doesn't wrap to zero. */
832 max_credit = vif->remaining_credit + vif->credit_bytes;
833 if (max_credit < vif->remaining_credit)
834 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
835
836 vif->remaining_credit = min(max_credit, max_burst);
837}
838
839static void tx_credit_callback(unsigned long data)
840{
841 struct xenvif *vif = (struct xenvif *)data;
842 tx_add_credit(vif);
843 xen_netbk_check_rx_xenvif(vif);
844}
845
846static void netbk_tx_err(struct xenvif *vif,
847 struct xen_netif_tx_request *txp, RING_IDX end)
848{
849 RING_IDX cons = vif->tx.req_cons;
850
851 do {
852 make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
853 if (cons >= end)
854 break;
855 txp = RING_GET_REQUEST(&vif->tx, cons++);
856 } while (1);
857 vif->tx.req_cons = cons;
858 xen_netbk_check_rx_xenvif(vif);
859 xenvif_put(vif);
860}
861
862static int netbk_count_requests(struct xenvif *vif,
863 struct xen_netif_tx_request *first,
864 struct xen_netif_tx_request *txp,
865 int work_to_do)
866{
867 RING_IDX cons = vif->tx.req_cons;
868 int frags = 0;
869
870 if (!(first->flags & XEN_NETTXF_more_data))
871 return 0;
872
873 do {
874 if (frags >= work_to_do) {
875 netdev_dbg(vif->dev, "Need more frags\n");
876 return -frags;
877 }
878
879 if (unlikely(frags >= MAX_SKB_FRAGS)) {
880 netdev_dbg(vif->dev, "Too many frags\n");
881 return -frags;
882 }
883
884 memcpy(txp, RING_GET_REQUEST(&vif->tx, cons + frags),
885 sizeof(*txp));
886 if (txp->size > first->size) {
887 netdev_dbg(vif->dev, "Frags galore\n");
888 return -frags;
889 }
890
891 first->size -= txp->size;
892 frags++;
893
894 if (unlikely((txp->offset + txp->size) > PAGE_SIZE)) {
895 netdev_dbg(vif->dev, "txp->offset: %x, size: %u\n",
896 txp->offset, txp->size);
897 return -frags;
898 }
899 } while ((txp++)->flags & XEN_NETTXF_more_data);
900 return frags;
901}
902
903static struct page *xen_netbk_alloc_page(struct xen_netbk *netbk,
904 struct sk_buff *skb,
ea066ad1 905 u16 pending_idx)
f942dc25
IC		 906{
907 struct page *page;
908 page = alloc_page(GFP_KERNEL|__GFP_COLD);
909 if (!page)
910 return NULL;
911 set_page_ext(page, netbk, pending_idx);
912 netbk->mmap_pages[pending_idx] = page;
913 return page;
914}
915
916static struct gnttab_copy *xen_netbk_get_requests(struct xen_netbk *netbk,
917 struct xenvif *vif,
918 struct sk_buff *skb,
919 struct xen_netif_tx_request *txp,
920 struct gnttab_copy *gop)
921{
922 struct skb_shared_info *shinfo = skb_shinfo(skb);
923 skb_frag_t *frags = shinfo->frags;
ea066ad1 924 u16 pending_idx = *((u16 *)skb->data);
f942dc25
IC		 925 int i, start;
926
927 /* Skip first skb fragment if it is on same page as header fragment. */
ea066ad1 928 start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
f942dc25
IC		 929
930 for (i = start; i < shinfo->nr_frags; i++, txp++) {
931 struct page *page;
932 pending_ring_idx_t index;
933 struct pending_tx_info *pending_tx_info =
934 netbk->pending_tx_info;
935
936 index = pending_index(netbk->pending_cons++);
937 pending_idx = netbk->pending_ring[index];
938 page = xen_netbk_alloc_page(netbk, skb, pending_idx);
939 if (!page)
940 return NULL;
941
f942dc25
IC		 942 gop->source.u.ref = txp->gref;
943 gop->source.domid = vif->domid;
944 gop->source.offset = txp->offset;
945
946 gop->dest.u.gmfn = virt_to_mfn(page_address(page));
947 gop->dest.domid = DOMID_SELF;
948 gop->dest.offset = txp->offset;
949
950 gop->len = txp->size;
951 gop->flags = GNTCOPY_source_gref;
952
953 gop++;
954
955 memcpy(&pending_tx_info[pending_idx].req, txp, sizeof(*txp));
956 xenvif_get(vif);
957 pending_tx_info[pending_idx].vif = vif;
ea066ad1 958 frag_set_pending_idx(&frags[i], pending_idx);
f942dc25
IC		 959 }
960
961 return gop;
962}
963
964static int xen_netbk_tx_check_gop(struct xen_netbk *netbk,
965 struct sk_buff *skb,
966 struct gnttab_copy **gopp)
967{
968 struct gnttab_copy *gop = *gopp;
ea066ad1 969 u16 pending_idx = *((u16 *)skb->data);
f942dc25
IC		 970 struct pending_tx_info *pending_tx_info = netbk->pending_tx_info;
971 struct xenvif *vif = pending_tx_info[pending_idx].vif;
972 struct xen_netif_tx_request *txp;
973 struct skb_shared_info *shinfo = skb_shinfo(skb);
974 int nr_frags = shinfo->nr_frags;
975 int i, err, start;
976
977 /* Check status of header. */
978 err = gop->status;
979 if (unlikely(err)) {
980 pending_ring_idx_t index;
981 index = pending_index(netbk->pending_prod++);
982 txp = &pending_tx_info[pending_idx].req;
983 make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
984 netbk->pending_ring[index] = pending_idx;
985 xenvif_put(vif);
986 }
987
988 /* Skip first skb fragment if it is on same page as header fragment. */
ea066ad1 989 start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
f942dc25
IC		 990
991 for (i = start; i < nr_frags; i++) {
992 int j, newerr;
993 pending_ring_idx_t index;
994
ea066ad1 995 pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
f942dc25
IC		 996
997 /* Check error status: if okay then remember grant handle. */
998 newerr = (++gop)->status;
999 if (likely(!newerr)) {
1000 /* Had a previous error? Invalidate this fragment. */
1001 if (unlikely(err))
1002 xen_netbk_idx_release(netbk, pending_idx);
1003 continue;
1004 }
1005
1006 /* Error on this fragment: respond to client with an error. */
1007 txp = &netbk->pending_tx_info[pending_idx].req;
1008 make_tx_response(vif, txp, XEN_NETIF_RSP_ERROR);
1009 index = pending_index(netbk->pending_prod++);
1010 netbk->pending_ring[index] = pending_idx;
1011 xenvif_put(vif);
1012
1013 /* Not the first error? Preceding frags already invalidated. */
1014 if (err)
1015 continue;
1016
1017 /* First error: invalidate header and preceding fragments. */
1018 pending_idx = *((u16 *)skb->data);
1019 xen_netbk_idx_release(netbk, pending_idx);
1020 for (j = start; j < i; j++) {
5ccb3ea7 1021 pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
f942dc25
IC		 1022 xen_netbk_idx_release(netbk, pending_idx);
1023 }
1024
1025 /* Remember the error: invalidate all subsequent fragments. */
1026 err = newerr;
1027 }
1028
1029 *gopp = gop + 1;
1030 return err;
1031}
1032
1033static void xen_netbk_fill_frags(struct xen_netbk *netbk, struct sk_buff *skb)
1034{
1035 struct skb_shared_info *shinfo = skb_shinfo(skb);
1036 int nr_frags = shinfo->nr_frags;
1037 int i;
1038
1039 for (i = 0; i < nr_frags; i++) {
1040 skb_frag_t *frag = shinfo->frags + i;
1041 struct xen_netif_tx_request *txp;
ea066ad1
IC		 1042 struct page *page;
1043 u16 pending_idx;
f942dc25 1044
ea066ad1 1045 pending_idx = frag_get_pending_idx(frag);
f942dc25
IC		 1046
1047 txp = &netbk->pending_tx_info[pending_idx].req;
ea066ad1
IC		 1048 page = virt_to_page(idx_to_kaddr(netbk, pending_idx));
1049 __skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
f942dc25
IC		 1050 skb->len += txp->size;
1051 skb->data_len += txp->size;
1052 skb->truesize += txp->size;
1053
1054 /* Take an extra reference to offset xen_netbk_idx_release */
1055 get_page(netbk->mmap_pages[pending_idx]);
1056 xen_netbk_idx_release(netbk, pending_idx);
1057 }
1058}
1059
1060static int xen_netbk_get_extras(struct xenvif *vif,
1061 struct xen_netif_extra_info *extras,
1062 int work_to_do)
1063{
1064 struct xen_netif_extra_info extra;
1065 RING_IDX cons = vif->tx.req_cons;
1066
1067 do {
1068 if (unlikely(work_to_do-- <= 0)) {
1069 netdev_dbg(vif->dev, "Missing extra info\n");
1070 return -EBADR;
1071 }
1072
1073 memcpy(&extra, RING_GET_REQUEST(&vif->tx, cons),
1074 sizeof(extra));
1075 if (unlikely(!extra.type ||
1076 extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
1077 vif->tx.req_cons = ++cons;
1078 netdev_dbg(vif->dev,
1079 "Invalid extra type: %d\n", extra.type);
1080 return -EINVAL;
1081 }
1082
1083 memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
1084 vif->tx.req_cons = ++cons;
1085 } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
1086
1087 return work_to_do;
1088}
1089
1090static int netbk_set_skb_gso(struct xenvif *vif,
1091 struct sk_buff *skb,
1092 struct xen_netif_extra_info *gso)
1093{
1094 if (!gso->u.gso.size) {
1095 netdev_dbg(vif->dev, "GSO size must not be zero.\n");
1096 return -EINVAL;
1097 }
1098
1099 /* Currently only TCPv4 S.O. is supported. */
1100 if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4) {
1101 netdev_dbg(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
1102 return -EINVAL;
1103 }
1104
1105 skb_shinfo(skb)->gso_size = gso->u.gso.size;
1106 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
1107
1108 /* Header must be checked, and gso_segs computed. */
1109 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
1110 skb_shinfo(skb)->gso_segs = 0;
1111
1112 return 0;
1113}
1114
1115static int checksum_setup(struct xenvif *vif, struct sk_buff *skb)
1116{
1117 struct iphdr *iph;
1118 unsigned char *th;
1119 int err = -EPROTO;
1120 int recalculate_partial_csum = 0;
1121
1122 /*
1123 * A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
1124 * peers can fail to set NETRXF_csum_blank when sending a GSO
1125 * frame. In this case force the SKB to CHECKSUM_PARTIAL and
1126 * recalculate the partial checksum.
1127 */
1128 if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
1129 vif->rx_gso_checksum_fixup++;
1130 skb->ip_summed = CHECKSUM_PARTIAL;
1131 recalculate_partial_csum = 1;
1132 }
1133
1134 /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
1135 if (skb->ip_summed != CHECKSUM_PARTIAL)
1136 return 0;
1137
1138 if (skb->protocol != htons(ETH_P_IP))
1139 goto out;
1140
1141 iph = (void *)skb->data;
1142 th = skb->data + 4 * iph->ihl;
1143 if (th >= skb_tail_pointer(skb))
1144 goto out;
1145
1146 skb->csum_start = th - skb->head;
1147 switch (iph->protocol) {
1148 case IPPROTO_TCP:
1149 skb->csum_offset = offsetof(struct tcphdr, check);
1150
1151 if (recalculate_partial_csum) {
1152 struct tcphdr *tcph = (struct tcphdr *)th;
1153 tcph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
1154 skb->len - iph->ihl*4,
1155 IPPROTO_TCP, 0);
1156 }
1157 break;
1158 case IPPROTO_UDP:
1159 skb->csum_offset = offsetof(struct udphdr, check);
1160
1161 if (recalculate_partial_csum) {
1162 struct udphdr *udph = (struct udphdr *)th;
1163 udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
1164 skb->len - iph->ihl*4,
1165 IPPROTO_UDP, 0);
1166 }
1167 break;
1168 default:
1169 if (net_ratelimit())
1170 netdev_err(vif->dev,
1171 "Attempting to checksum a non-TCP/UDP packet, dropping a protocol %d packet\n",
1172 iph->protocol);
1173 goto out;
1174 }
1175
1176 if ((th + skb->csum_offset + 2) > skb_tail_pointer(skb))
1177 goto out;
1178
1179 err = 0;
1180
1181out:
1182 return err;
1183}
1184
1185static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
1186{
1187 unsigned long now = jiffies;
1188 unsigned long next_credit =
1189 vif->credit_timeout.expires +
1190 msecs_to_jiffies(vif->credit_usec / 1000);
1191
1192 /* Timer could already be pending in rare cases. */
1193 if (timer_pending(&vif->credit_timeout))
1194 return true;
1195
1196 /* Passed the point where we can replenish credit? */
1197 if (time_after_eq(now, next_credit)) {
1198 vif->credit_timeout.expires = now;
1199 tx_add_credit(vif);
1200 }
1201
1202 /* Still too big to send right now? Set a callback. */
1203 if (size > vif->remaining_credit) {
1204 vif->credit_timeout.data =
1205 (unsigned long)vif;
1206 vif->credit_timeout.function =
1207 tx_credit_callback;
1208 mod_timer(&vif->credit_timeout,
1209 next_credit);
1210
1211 return true;
1212 }
1213
1214 return false;
1215}
1216
1217static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk)
1218{
1219 struct gnttab_copy *gop = netbk->tx_copy_ops, *request_gop;
1220 struct sk_buff *skb;
1221 int ret;
1222
1223 while (((nr_pending_reqs(netbk) + MAX_SKB_FRAGS) < MAX_PENDING_REQS) &&
1224 !list_empty(&netbk->net_schedule_list)) {
1225 struct xenvif *vif;
1226 struct xen_netif_tx_request txreq;
1227 struct xen_netif_tx_request txfrags[MAX_SKB_FRAGS];
1228 struct page *page;
1229 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
1230 u16 pending_idx;
1231 RING_IDX idx;
1232 int work_to_do;
1233 unsigned int data_len;
1234 pending_ring_idx_t index;
1235
1236 /* Get a netif from the list with work to do. */
1237 vif = poll_net_schedule_list(netbk);
1238 if (!vif)
1239 continue;
1240
1241 RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, work_to_do);
1242 if (!work_to_do) {
1243 xenvif_put(vif);
1244 continue;
1245 }
1246
1247 idx = vif->tx.req_cons;
1248 rmb(); /* Ensure that we see the request before we copy it. */
1249 memcpy(&txreq, RING_GET_REQUEST(&vif->tx, idx), sizeof(txreq));
1250
1251 /* Credit-based scheduling. */
1252 if (txreq.size > vif->remaining_credit &&
1253 tx_credit_exceeded(vif, txreq.size)) {
1254 xenvif_put(vif);
1255 continue;
1256 }
1257
1258 vif->remaining_credit -= txreq.size;
1259
1260 work_to_do--;
1261 vif->tx.req_cons = ++idx;
1262
1263 memset(extras, 0, sizeof(extras));
1264 if (txreq.flags & XEN_NETTXF_extra_info) {
1265 work_to_do = xen_netbk_get_extras(vif, extras,
1266 work_to_do);
1267 idx = vif->tx.req_cons;
1268 if (unlikely(work_to_do < 0)) {
1269 netbk_tx_err(vif, &txreq, idx);
1270 continue;
1271 }
1272 }
1273
1274 ret = netbk_count_requests(vif, &txreq, txfrags, work_to_do);
1275 if (unlikely(ret < 0)) {
1276 netbk_tx_err(vif, &txreq, idx - ret);
1277 continue;
1278 }
1279 idx += ret;
1280
1281 if (unlikely(txreq.size < ETH_HLEN)) {
1282 netdev_dbg(vif->dev,
1283 "Bad packet size: %d\n", txreq.size);
1284 netbk_tx_err(vif, &txreq, idx);
1285 continue;
1286 }
1287
1288 /* No crossing a page as the payload mustn't fragment. */
1289 if (unlikely((txreq.offset + txreq.size) > PAGE_SIZE)) {
1290 netdev_dbg(vif->dev,
1291 "txreq.offset: %x, size: %u, end: %lu\n",
1292 txreq.offset, txreq.size,
1293 (txreq.offset&~PAGE_MASK) + txreq.size);
1294 netbk_tx_err(vif, &txreq, idx);
1295 continue;
1296 }
1297
1298 index = pending_index(netbk->pending_cons);
1299 pending_idx = netbk->pending_ring[index];
1300
1301 data_len = (txreq.size > PKT_PROT_LEN &&
1302 ret < MAX_SKB_FRAGS) ?
1303 PKT_PROT_LEN : txreq.size;
1304
1305 skb = alloc_skb(data_len + NET_SKB_PAD + NET_IP_ALIGN,
1306 GFP_ATOMIC | __GFP_NOWARN);
1307 if (unlikely(skb == NULL)) {
1308 netdev_dbg(vif->dev,
1309 "Can't allocate a skb in start_xmit.\n");
1310 netbk_tx_err(vif, &txreq, idx);
1311 break;
1312 }
1313
1314 /* Packets passed to netif_rx() must have some headroom. */
1315 skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
1316
1317 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1318 struct xen_netif_extra_info *gso;
1319 gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1320
1321 if (netbk_set_skb_gso(vif, skb, gso)) {
1322 kfree_skb(skb);
1323 netbk_tx_err(vif, &txreq, idx);
1324 continue;
1325 }
1326 }
1327
1328 /* XXX could copy straight to head */
1329 page = xen_netbk_alloc_page(netbk, skb, pending_idx);
1330 if (!page) {
1331 kfree_skb(skb);
1332 netbk_tx_err(vif, &txreq, idx);
1333 continue;
1334 }
1335
f942dc25
IC		 1336 gop->source.u.ref = txreq.gref;
1337 gop->source.domid = vif->domid;
1338 gop->source.offset = txreq.offset;
1339
1340 gop->dest.u.gmfn = virt_to_mfn(page_address(page));
1341 gop->dest.domid = DOMID_SELF;
1342 gop->dest.offset = txreq.offset;
1343
1344 gop->len = txreq.size;
1345 gop->flags = GNTCOPY_source_gref;
1346
1347 gop++;
1348
1349 memcpy(&netbk->pending_tx_info[pending_idx].req,
1350 &txreq, sizeof(txreq));
1351 netbk->pending_tx_info[pending_idx].vif = vif;
1352 *((u16 *)skb->data) = pending_idx;
1353
1354 __skb_put(skb, data_len);
1355
1356 skb_shinfo(skb)->nr_frags = ret;
1357 if (data_len < txreq.size) {
1358 skb_shinfo(skb)->nr_frags++;
ea066ad1
IC		 1359 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1360 pending_idx);
f942dc25 1361 } else {
ea066ad1
IC		 1362 frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1363 INVALID_PENDING_IDX);
f942dc25
IC		 1364 }
1365
1366 __skb_queue_tail(&netbk->tx_queue, skb);
1367
1368 netbk->pending_cons++;
1369
1370 request_gop = xen_netbk_get_requests(netbk, vif,
1371 skb, txfrags, gop);
1372 if (request_gop == NULL) {
1373 kfree_skb(skb);
1374 netbk_tx_err(vif, &txreq, idx);
1375 continue;
1376 }
1377 gop = request_gop;
1378
1379 vif->tx.req_cons = idx;
1380 xen_netbk_check_rx_xenvif(vif);
1381
1382 if ((gop-netbk->tx_copy_ops) >= ARRAY_SIZE(netbk->tx_copy_ops))
1383 break;
1384 }
1385
1386 return gop - netbk->tx_copy_ops;
1387}
1388
1389static void xen_netbk_tx_submit(struct xen_netbk *netbk)
1390{
1391 struct gnttab_copy *gop = netbk->tx_copy_ops;
1392 struct sk_buff *skb;
1393
1394 while ((skb = __skb_dequeue(&netbk->tx_queue)) != NULL) {
1395 struct xen_netif_tx_request *txp;
1396 struct xenvif *vif;
1397 u16 pending_idx;
1398 unsigned data_len;
1399
1400 pending_idx = *((u16 *)skb->data);
1401 vif = netbk->pending_tx_info[pending_idx].vif;
1402 txp = &netbk->pending_tx_info[pending_idx].req;
1403
1404 /* Check the remap error code. */
1405 if (unlikely(xen_netbk_tx_check_gop(netbk, skb, &gop))) {
1406 netdev_dbg(vif->dev, "netback grant failed.\n");
1407 skb_shinfo(skb)->nr_frags = 0;
1408 kfree_skb(skb);
1409 continue;
1410 }
1411
1412 data_len = skb->len;
1413 memcpy(skb->data,
1414 (void *)(idx_to_kaddr(netbk, pending_idx)|txp->offset),
1415 data_len);
1416 if (data_len < txp->size) {
1417 /* Append the packet payload as a fragment. */
1418 txp->offset += data_len;
1419 txp->size -= data_len;
1420 } else {
1421 /* Schedule a response immediately. */
1422 xen_netbk_idx_release(netbk, pending_idx);
1423 }
1424
1425 if (txp->flags & XEN_NETTXF_csum_blank)
1426 skb->ip_summed = CHECKSUM_PARTIAL;
1427 else if (txp->flags & XEN_NETTXF_data_validated)
1428 skb->ip_summed = CHECKSUM_UNNECESSARY;
1429
1430 xen_netbk_fill_frags(netbk, skb);
1431
1432 /*
1433 * If the initial fragment was < PKT_PROT_LEN then
1434 * pull through some bytes from the other fragments to
1435 * increase the linear region to PKT_PROT_LEN bytes.
1436 */
1437 if (skb_headlen(skb) < PKT_PROT_LEN && skb_is_nonlinear(skb)) {
1438 int target = min_t(int, skb->len, PKT_PROT_LEN);
1439 __pskb_pull_tail(skb, target - skb_headlen(skb));
1440 }
1441
1442 skb->dev = vif->dev;
1443 skb->protocol = eth_type_trans(skb, skb->dev);
1444
1445 if (checksum_setup(vif, skb)) {
1446 netdev_dbg(vif->dev,
1447 "Can't setup checksum in net_tx_action\n");
1448 kfree_skb(skb);
1449 continue;
1450 }
1451
1452 vif->dev->stats.rx_bytes += skb->len;
1453 vif->dev->stats.rx_packets++;
1454
1455 xenvif_receive_skb(vif, skb);
1456 }
1457}
1458
1459/* Called after netfront has transmitted */
1460static void xen_netbk_tx_action(struct xen_netbk *netbk)
1461{
1462 unsigned nr_gops;
1463 int ret;
1464
1465 nr_gops = xen_netbk_tx_build_gops(netbk);
1466
1467 if (nr_gops == 0)
1468 return;
1469 ret = HYPERVISOR_grant_table_op(GNTTABOP_copy,
1470 netbk->tx_copy_ops, nr_gops);
1471 BUG_ON(ret);
1472
1473 xen_netbk_tx_submit(netbk);
1474
1475}
1476
1477static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx)
1478{
1479 struct xenvif *vif;
1480 struct pending_tx_info *pending_tx_info;
1481 pending_ring_idx_t index;
1482
1483 /* Already complete? */
1484 if (netbk->mmap_pages[pending_idx] == NULL)
1485 return;
1486
1487 pending_tx_info = &netbk->pending_tx_info[pending_idx];
1488
1489 vif = pending_tx_info->vif;
1490
1491 make_tx_response(vif, &pending_tx_info->req, XEN_NETIF_RSP_OKAY);
1492
1493 index = pending_index(netbk->pending_prod++);
1494 netbk->pending_ring[index] = pending_idx;
1495
1496 xenvif_put(vif);
1497
1498 netbk->mmap_pages[pending_idx]->mapping = 0;
1499 put_page(netbk->mmap_pages[pending_idx]);
1500 netbk->mmap_pages[pending_idx] = NULL;
1501}
1502
1503static void make_tx_response(struct xenvif *vif,
1504 struct xen_netif_tx_request *txp,
1505 s8 st)
1506{
1507 RING_IDX i = vif->tx.rsp_prod_pvt;
1508 struct xen_netif_tx_response *resp;
1509 int notify;
1510
1511 resp = RING_GET_RESPONSE(&vif->tx, i);
1512 resp->id = txp->id;
1513 resp->status = st;
1514
1515 if (txp->flags & XEN_NETTXF_extra_info)
1516 RING_GET_RESPONSE(&vif->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1517
1518 vif->tx.rsp_prod_pvt = ++i;
1519 RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->tx, notify);
1520 if (notify)
1521 notify_remote_via_irq(vif->irq);
1522}
1523
1524static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
1525 u16 id,
1526 s8 st,
1527 u16 offset,
1528 u16 size,
1529 u16 flags)
1530{
1531 RING_IDX i = vif->rx.rsp_prod_pvt;
1532 struct xen_netif_rx_response *resp;
1533
1534 resp = RING_GET_RESPONSE(&vif->rx, i);
1535 resp->offset = offset;
1536 resp->flags = flags;
1537 resp->id = id;
1538 resp->status = (s16)size;
1539 if (st < 0)
1540 resp->status = (s16)st;
1541
1542 vif->rx.rsp_prod_pvt = ++i;
1543
1544 return resp;
1545}
1546
1547static inline int rx_work_todo(struct xen_netbk *netbk)
1548{
1549 return !skb_queue_empty(&netbk->rx_queue);
1550}
1551
1552static inline int tx_work_todo(struct xen_netbk *netbk)
1553{
1554
1555 if (((nr_pending_reqs(netbk) + MAX_SKB_FRAGS) < MAX_PENDING_REQS) &&
1556 !list_empty(&netbk->net_schedule_list))
1557 return 1;
1558
1559 return 0;
1560}
1561
1562static int xen_netbk_kthread(void *data)
1563{
1564 struct xen_netbk *netbk = data;
1565 while (!kthread_should_stop()) {
1566 wait_event_interruptible(netbk->wq,
1567 rx_work_todo(netbk) ||
1568 tx_work_todo(netbk) ||
1569 kthread_should_stop());
1570 cond_resched();
1571
1572 if (kthread_should_stop())
1573 break;
1574
1575 if (rx_work_todo(netbk))
1576 xen_netbk_rx_action(netbk);
1577
1578 if (tx_work_todo(netbk))
1579 xen_netbk_tx_action(netbk);
1580 }
1581
1582 return 0;
1583}
1584
1585void xen_netbk_unmap_frontend_rings(struct xenvif *vif)
1586{
c9d63699
DV		 1587 if (vif->tx.sring)
1588 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
1589 vif->tx.sring);
1590 if (vif->rx.sring)
1591 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
1592 vif->rx.sring);
f942dc25
IC		 1593}
1594
1595int xen_netbk_map_frontend_rings(struct xenvif *vif,
1596 grant_ref_t tx_ring_ref,
1597 grant_ref_t rx_ring_ref)
1598{
c9d63699 1599 void *addr;
f942dc25
IC		 1600 struct xen_netif_tx_sring *txs;
1601 struct xen_netif_rx_sring *rxs;
1602
1603 int err = -ENOMEM;
1604
c9d63699
DV		 1605 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
1606 tx_ring_ref, &addr);
1607 if (err)
f942dc25
IC		 1608 goto err;
1609
c9d63699 1610 txs = (struct xen_netif_tx_sring *)addr;
f942dc25
IC		 1611 BACK_RING_INIT(&vif->tx, txs, PAGE_SIZE);
1612
c9d63699
DV		 1613 err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
1614 rx_ring_ref, &addr);
1615 if (err)
f942dc25 1616 goto err;
f942dc25 1617
c9d63699 1618 rxs = (struct xen_netif_rx_sring *)addr;
f942dc25
IC		 1619 BACK_RING_INIT(&vif->rx, rxs, PAGE_SIZE);
1620
c9d63699
DV		 1621 vif->rx_req_cons_peek = 0;
1622
f942dc25
IC		 1623 return 0;
1624
1625err:
1626 xen_netbk_unmap_frontend_rings(vif);
1627 return err;
1628}
1629
1630static int __init netback_init(void)
1631{
1632 int i;
1633 int rc = 0;
1634 int group;
1635
2a14b244 1636 if (!xen_domain())
f942dc25
IC		 1637 return -ENODEV;
1638
1639 xen_netbk_group_nr = num_online_cpus();
1640 xen_netbk = vzalloc(sizeof(struct xen_netbk) * xen_netbk_group_nr);
e404decb 1641 if (!xen_netbk)
f942dc25 1642 return -ENOMEM;
f942dc25
IC		 1643
1644 for (group = 0; group < xen_netbk_group_nr; group++) {
1645 struct xen_netbk *netbk = &xen_netbk[group];
1646 skb_queue_head_init(&netbk->rx_queue);
1647 skb_queue_head_init(&netbk->tx_queue);
1648
1649 init_timer(&netbk->net_timer);
1650 netbk->net_timer.data = (unsigned long)netbk;
1651 netbk->net_timer.function = xen_netbk_alarm;
1652
1653 netbk->pending_cons = 0;
1654 netbk->pending_prod = MAX_PENDING_REQS;
1655 for (i = 0; i < MAX_PENDING_REQS; i++)
1656 netbk->pending_ring[i] = i;
1657
1658 init_waitqueue_head(&netbk->wq);
1659 netbk->task = kthread_create(xen_netbk_kthread,
1660 (void *)netbk,
1661 "netback/%u", group);
1662
1663 if (IS_ERR(netbk->task)) {
6b84bd16 1664 printk(KERN_ALERT "kthread_create() fails at netback\n");
f942dc25
IC		 1665 del_timer(&netbk->net_timer);
1666 rc = PTR_ERR(netbk->task);
1667 goto failed_init;
1668 }
1669
1670 kthread_bind(netbk->task, group);
1671
1672 INIT_LIST_HEAD(&netbk->net_schedule_list);
1673
1674 spin_lock_init(&netbk->net_schedule_list_lock);
1675
1676 atomic_set(&netbk->netfront_count, 0);
1677
1678 wake_up_process(netbk->task);
1679 }
1680
1681 rc = xenvif_xenbus_init();
1682 if (rc)
1683 goto failed_init;
1684
1685 return 0;
1686
1687failed_init:
1688 while (--group >= 0) {
1689 struct xen_netbk *netbk = &xen_netbk[group];
1690 for (i = 0; i < MAX_PENDING_REQS; i++) {
1691 if (netbk->mmap_pages[i])
1692 __free_page(netbk->mmap_pages[i]);
1693 }
1694 del_timer(&netbk->net_timer);
1695 kthread_stop(netbk->task);
1696 }
1697 vfree(xen_netbk);
1698 return rc;
1699
1700}
1701
1702module_init(netback_init);
1703
1704MODULE_LICENSE("Dual BSD/GPL");
f984cec6 1705MODULE_ALIAS("xen-backend:vif");
Linux 6.x block layer and io_uring tree(s)